1. Field of the Invention
This invention relates to position sensors. In particular, this invention relates to a position sensor that has a modular design for easy coupling to another modular device.
2. Description of Related Art
Various devices and methods of dealing with the design of position sensors are legion. Examples of patents related to the present invention are as follows, and each patent is herein incorporated by reference for the supporting teachings:
U.S. Pat. No. 5,828,290 is a modular position sensor with pin holes in the bottom thereof; PA1 U.S. Pat. No. 5,460,035 is a bearing-free spring-free throttle position sensor; PA1 U.S. Pat. No. 5,416,295 is a combined pedal force switch and position sensor; PA1 U.S. Pat. No. 5,385,068 is an electronic accelerator pedal assembly with pedal force sensor; PA1 U.S. Pat. No. 5,321,980 is an integrated throttle position sensor with independent position validation sensor; PA1 U.S. Pat. No. 5,133,321 is an integrated throttle control and idle validation sensor; PA1 U.S. Pat. No. 4,688,420 is a throttle valve position detecting device for a vehicle engine; PA1 U.S. Pat. No. 4,430,634 is a rotary potentiometer with molded terminal package; PA1 U.S. Pat. No. 4,616,504 is a throttle position sensor with a potentiometer module that fits into a connector casing; and
The foregoing patents reflect the state of the art, of which the applicants are aware, and are tendered with the view toward discharging applicants' acknowledged duty of candor in disclosing information that may be pertinent in the examination of this application. It is respectfully stipulated, however, that none of these patents teach or render obvious, singly, or when considered in combination, the applicants' claimed invention.
3. Problems with Related Art
There are several common problems occurring with the related art. For example, a problem with previous modular designs is the scratching of the flexible film potentiometer that is positioned within the sensor housing. This occurs when the film is brought in direct contact with the pins or electrical leads that are disposed on the external device to which the sensor unit is coupled. In one previous design, the external device's pins penetrate the sensor housing through holes disposed in the base thereof. Once inside the sensor housing, the pins are brought in direct contact with output pads positioned along the flexible film. Such contact causes scratching of the output pads and, accordingly, potentially causing degraded performance of the sensor device.
FIGS. 1 and 2 show one example of such a related art sensor device. As shown, sensor unit 100 is provided with holes 117 in the base 139 thereof, a pressure wall 138 affixed to base 139, pressure wedges 136, and flexible film 130 having output pads 132 thereon. Pressure wedges 136 force flexible film 130 away from pressure wall 138 so that when sensor unit 100 is slid over an external device (not shown), pins 122, positioned on the external device, will protrude through holes 117 and directly contact output pads 132. However, the sliding of pins 122 against output pads 132 causes scratching to output pads 132 and, accordingly, degraded sensor unit 100 performance.
An additional problem with previous sensor devices is that it can be more expensive to make all of the variations for connecting the same sensor unit to different devices. In particular, a sensor unit may need a female connection, a male connection, a pig tail connection, or connections that are angled, etc. It is expensive to build a different assembly line for every type of connector that is integrally attached to the same sensor unit. It would be less expensive to have one assembly line to make all sensor units and test them, and have other standard assembly lines that produce the various types of connectors for mounting the sensor unit thereto. Therefore, there is a need for a modular sensor unit that can be attached to either a modular connector or another device, such as a gas pedal.
Another problem with the prior art is that it is more expensive to build sensor units with metal leads or pins that are permanently attached to the signal traces or output pads that are usually located on flexible films. The elimination of the permanent metal leads or pins from a modular sensor could lower the cost of making the sensor units. Therefore, there is a need for a less expensive sensor unit that can eliminate the use of permanently attached electrical leads or pins attached to, for example, the output pads on flexible films.
The preferred embodiment of the invention is designed to solve the problems herein described and other problems not discussed, which are discoverable by a skilled artisan.